A very cold and unstable storm out of the Gulf of Alaska will drop into Southern California late Monday night or early Tuesday and dump 16 to 18 inches of snow above the 5,000 foot level in the county's mountains and produce flakes down to 2,000 feet, creating hazardous driving in East County.

The National Weather Service says the storm also will drop from a half-inch to one inch of rain west of the mountains and one to two inches of rain in the mountains, mostly from Tuesday afternoon into early Wednesday. In some areas, mountain winds could gust up to 75 mph, briefly becoming as strong as a category one hurricane. The atmosphere will be very unstable throughout the storm, raising the possibility of thunderstorms, hail, and water spouts.

The snow will affect travel on eastern Interstate 8, and authorities will require motorists to put chains on the tires of their vehicles in such places as Sunrise Highway. A winter storm warning has been posted.

"There's a secondary system behind this that could bring some rain into Thursday," said Cindy Palmer, a weather service forecaster.

It's possible that the region will make up some of its rain deficit. Since the rainy season officially began on July 1, 2012, San Diego's Lindbergh Field has recorded 4.65'' of precipitation, which is almost 2'' below normal.